Flat articles, such as e.g. printed products, are conveyed suspended in a conveying or feed flow, in that a conveying means, e.g. clips or grippers engage on the upper edge of each printed product. From such a suspended conveying movement, by simply opening the conveying means the printed products are individually conveyed downwards by gravity to some other processing stage, while the conveying means continue to move on in a substantially linear manner. A use example of such a suspended supply to a processing stage is the supply to a processing drum in which e.g. preliminary products and/or inserts are inserted in printed products. A corresponding apparatus with a suspended feed is described in U.S. Pat. No. 4,801,132 (corresponding to Swiss patent 668 244) and the latter patent specification is assumed as known.
The advantage of a suspended or hanging supply or feed is that the conveying means do not have to be guided in the immediate vicinity of the feed. Thus, the actual feed is undisturbed and the conveying means can be led away in simple manner from the feed point. The suspended printed product is supplied with the lower edge leading. This means that the accuracy of the feed is dependent on the positioning accuracy of said lower edge. For sufficiently rigid, relatively slowly conveyed printed products such a feed constitutes no problem because the position of the lower edge is relatively accurately defined and is always positioned perpendicularly above the upper edge. Therefore feed can take place in a locally closely defined manner. As described in the aforementioned patent, it is also possible to engage the lower edges of the suspended printed products shortly upstream of the feed point with a conveyor belt running parallel to the conveying direction and in this way stabilize the same. If the speed of the conveyor belt is the same as the conveying speed, the printed products will reach the feed point in the vertical position. If the conveyor belt speed is not precisely the same as the speed of the conveying elements, then the lower edge of the printed products is accelerated or decelerated compared with the upper edge and at the feed point the printed products have a slightly inclined position, which can be advantageous for the supply, e.g. to a processing drum.
However, if the printed products conveyed in a suspended manner are not particularly rigid and also the conveying speed is so high that there is significant air resistance, the position of the lower edge of the printed products is not defined and consequently precise feeding with the lower edge to the front is problematical. Thus, if the feed or supply must be clearly defined in such a case, the spacings between the individual printed products in the feed flow must be very large and the feed point must be very wide. For a given production rate, this leads to higher conveying speeds and therefore to higher air resistances and is consequently inappropriate for achieving a precise speed. A guidance of the lower edge of the printed products with additional clips or grippers, which secure the lower edge of said products, is conceivable, but expensive from the apparatus standpoint, because the additional clips must continue over the entire feeding or conveying path, because as soon as the air resistance acts on the printed products, they can no longer engage on the latter due to the undefined position of the lower edges. It is also disadvantageous in the case of sensitive printed products to secure them with more clips than are absolutely necessary.